Total depth after etching is 9.138 um
Calculated remaining resist as 8.66um, indicating an erosion of 0.08um in 10 minutes of etching
This equates to an erosion rate of 8 nm/min
The etch depth of 0.48um in 10 mins indicates an etch rate of 48.0nm/min
The selectivity is therefore 5.77:1